A modeling study of stress and strain formation induced during melting process in powder-bed electron beam melting for Ni superalloy

In order to decrease deformation and stress in powder-bed electron beam melting, clarification of the characteristics of strain and stress formation during the melting process would be of great benefit. We developed an FE-based 3D thermal elastoplastic model with a Gaussian heat flux distribution profile in raster scanning pattern for Ni superalloy Rene 80 It was confirmed that strain variation in simulation showed good agreement with values calculated by a proposed mechanical model and proved to be quantitatively valid. The stress distribution during the melting process showed anisotropy in that the stresses in the beam scanning direction were higher than those in the other directions. The anisotropy formation mechanism was explicable by plastic strain anisotropy dominated by the restraint condition in that orthogonal direction was free boundary and lengthwise direction was subjected to restraint.